Clinical And Experimental Research Of Hip Resurfacing Arthroplasty And The Exploitation Of Orthopedics Cases Registration System

Hip resurfacing is not a new concept and attempts to treat hip arthritis without resetting the femoral head and neck have been made since the 1950s.The current generation of metal-on-metal hip resurfacing arthroplasty components is the third attempt by their pro-ponents to eliminate a femoralcomponent inserted into the diaphysis.The first generation involved cemented poly-ethylene acetabular and stemless femoral components.After initial enthusiasm,the high rate of failure, resulting from femoral neck fracture,femoral component loosening,and late acetabular component loosening,led to its abandonme nt Revision of failed resurfacing was problem-atic as a result of large acetabular deficiencies in many hips. These condgeneration of resurfacing involved the use of porous-coated uncemented components with a chamfered cylinder for acetabular fixation and a stemless femoral component.However,this prosthesis was never widely used.Large osteolytic lesions in the pelvisoc-curred in 17%of hips with this prosthesis,and failure of this generation of resurfacing was related to the polyethylene bearing surface.With a large-diameter femoral head and a polyethylene liner,the generation of particulate wear debris was substantial in these generally young and active patients.The third generation of resurfacing involved a so-called hybrid concept;acementless, porous-coated,nonmodular acetabular component;and a stemmed femoral component implanted with bone cement.The resurgence of new and better-engineered metal-on-metal bearings has provided the means to develop aviable prosthetic solution from a concept that was once abandoned.The lessons drawn from the early resurfacing era led to modern designs allusing a cementless fixation of the acetabula component and a short metaphyseal stem designed for component alignment on the femoral side.Currently,only metallic devices can be manufactured with sucient strength as a thin one-piece shell,combining excellent wear properties for large femoral heads and a bone conserving device on the acetabular side.The early results of these new designs are extremel encouraging but the rapid development of the procedure needs to be controlled by appropriate training programmes to ensure its future success.and the techniche has been looked on as one of the most important recent evolutions of hip arthroplasty.At present,owing to the improvement of metal-on-metal beatings and surgical techniques,short- and mid-term results are very good and encourage wider use of this technique,especially in the younger and more active patients.13 cases at our department between August 3,2005,and May 1,2007.All patients reported for the scheduled follow-up and were included in the study,there were no intraoperative complications,infections,peripheral nerve palsy,hip dislocations or clinically overt vein thrombosis.All of the patients reported complete or major pain relief.the short term result of the groups are good.At the same time,complications associated with hip resurfacing include fracture of femoral neck,avascular necrosis(AVN) of the head,raised the levels of metal ions in the blood,and long term of fixation cause people noticed,especially the problem of femoral neck fracture after hip resuring has become one of hot study points at present.Although at first sight all designs of resurfacing femoral head look the same,there are subtle variations in design that may influence the load transfer with in the femoral head.There are a number of factors likely to influence the loads.The finite element method is an ideal tool to study the stress distribution in all parts of the device.and the result can help doctors and engineering to find the factors influence the femoral neck fracture after hip resuring.Part 1 Clinical Research of Revision and Stress Finite Elemental Analysis of hip resurfacing arthroplastyChapter one The study and short-term clinical follow-up of mental on mental hip resurfacing arthroplastyBACKGROUND:Following the reintroduction of metal-on-metal articulating surfaces for total hip arthroplasty in Europe in 1988,from 2005 we developed a surface arthroplasty prosthetic system using a metal-on-metal articulation.The present study describes the clinical and radio-graphic results of the first 13 hips treated with metal-on-metalhybrid surface arthroplasties at an average follow-up of 24 months.Objective:1.To evaluate the short-term result of mental on mental hip resurfacing arthroplasty and analyses factors affecting the result.2.To compare the restoration of hip mechanics after resurfacing and account for the improved dynamics.METHODS:We performed 13 hip resurfacing arthroplasties at our department between August 3,2005,and May 1,2007.The implants used were the zimmer-duron Hip Resurfacing arthroplasty.A posterior approach was used with release of the insertion of gluteus maximus and circumferential capsulotomy.Radiographs were templated before surgery in all patients.All patients reported for the scheduled follow-up and were included in the study. Treatment outcomes were assessed according to the Harris Hip Score. Measurements were taken from standardised post-operative anteroposterior radiographs of the pelvis centred on the symphysis pubis,The post-operative radiograph of the operated hip was compared with the contralateral hip,in order to eliminate the changes in the hip biomechanics from pre-operative morbidity in the operated hip. Stastical analyses:the qualitation data would be described by mean±standard deviation;before been analysised;all datas should be tested by independence sample T test;all these test would be finished by SPSS11.0 stastical soft.RESULTS:The short-term outcomes of hip resurfacing arthroplasties are encouraging.In the study group there were no intraoperative complications, infections,peripheral nerve palsy,hip dislocations or clinically overt vein thrombosis. All of the patients reported complete or major pain relief.Clinical assessment according to the Harris Hip Score revealed improvement from an average of 36.69±7.16 points preoperatively to an average of 89.63±3.36 points after the surgery..Compared the post-operation Harris Hip Score with the pre-operation Harris Hip Score;significant difference could be found(t=24.377,p＜0.001).Crutches were used for a maximum of 4 weeks postoperatively.All of the patients are currently able to walk without crutches with full weight-bearing.The absolute differences in the post-operative and control measurements were small.The greatest change was in femoral offset which was reduced in the hip resurfacing artroplasty group by a mean of 5.45 mm.the pre-operative femoral offset is 51.04±3.83,the post-operative femoral offset is 45.59±3.61.the femoral offset was significantly reduced(t=8.50,p＜0.001).CONCLUSIONS:1) Hip resurfacing arthroplasty seems to be an advisable method of operative management of younger,active patients,2) Despite the good short- and mid-term results,the utility of this method should be evaluated with caution due to the lack of adequate long-term follow-up data.3) Reproduction of hip mechanics after resurfacing are not as good as has been suggested.There are a number of variations in the surgical technique which could produce the changes which we have demonstrated.Although the reduced offset should bedetrimental to normal function,the difference,is likely to be clinically insignificant.Chapter two The Setup Finite Element Model of hip resurfacing arthroplasty System and Biomechanics AnalysisObjective:1.Set up the hip resurfacing arthroplasty systems' finite element model,and master the stress distribution under physiological loads.2.To analyze the stress distribution on the femoral neck after the hip resurfacing arthroplasty to provide biomechanical evidence for the improvement of hip resurfacing arthroplasty surgical plan.3.To analyze the different stress distribution on the different part of femoral neck after the hip resurfacing arthroplasty,and analyses Stress shielding inside the femoral head exist or not.Method Three-dimensional FE model sofan intact right proximal femur and aproximal femur with resurfaced femoral head were developed using computed tomography(CT) scan data and the solid modeler of abaqus(6.5)FE software.The femur was implanted with a 48 mm diameter femoral head resurfacing prosthesis(zimmer duron).The inner surface of the implant was fixed to the bone using bone-cement(PMMA).The tapered stem was inserted into aparallel side hole and was modeled as completely debonded.The Young's modulus for the PMMA and the implant were assumed to be 2500 and 235000 MPa,respectively.A Poisson's ratio of 0.3 was assumed for all materials.Mesh generation and solutions were obtained using simpleware 2.1 and abaqus 6.5 software.the model were divided into 5 parts:acetabular prosthesis,femoral prosthesis,bone cement,os integumentale and cancellous bone.The model were divided by hexahedron unit.the part of acetabular prosthesis contains 5465unit and 11062 nodes,the part of femoral prosthesis contains 6883 unit and 9880 nodes.the part of bone cement contains 9829 units and 12295 nodes;the part of os integumentale contains 80222 units and 104306 nodes,the part of cancellous bone contains 62346 units and 73689 nodes.the FE model were analysed by abaqus 6.5.These loading conditions were applied to the FE model as static load cases.The body weight was assumed to be 70kg.these loads were uniformly distributed over the area of contact(for the hip joint reaction force).Nodes located on the distal end of the femur were constrained in all directions.The femoral part of model were divided into 8 parts,the stress distribution and straining were measured;measure the Yon Misses stress on different points;the qualitation data would be described by mean±standard deviation;before been analysised;all datas should be tested by one-way anova;all these test would be finished by SPSS11.0 stastical soft.Result:1.Peak strain throughout the bone remodeling process is presented in the superior femoral neck in the resurfaced femur.2.Post-operatively,strainshielding was observed inside the proximal femoral head.Reduction of strain was observed in the superior femoral head as compared to the intact femurConclusion:1.Peak strain concentrations occurr at neck of femoral,inferiorly and superiorly at the head-neck junction,in order to reduce the ratio of bone fracture of fermoral neck,the bone of femoral neck especially superiorly part of neck should be noticed during the operation.2.Stress shielding exists inside the femoral head after hip resurfacing plasty. Which caused changes in bone density within the resurfaced femoral head,and would lead to bone remodeling and consequently reduction in bone density in the superior femora head region.Part 2 The exploitation and apply of orthopedics cases registration analytical systemBackground:following the development of science and technology and the advancement of biology research,more and more artificial implants and treatments are being applied for clinical use.While the evaluation methods exhibit some extent of hysteresis,due to the prolongation of their clinical application.However,it is essential to build some form of document registration and clinical evaluation system for the development of orthopedics.Nowadays there hasn't been a systematic commercial orthopedic case file registration system which has been generally used yet.The aim of this research is to develop a free-of-charge open orthopedic case file registration system that is based on network registration,and can facilitate the registration of the clinical doctor's workstation,as well as could be used as the evaluation of the actual clinical therapeutic efficacy of new treatments and new instruments.The pre-assessment of new evaluation method based on improvement of the traditional evaluation method could be achieveed on the platform.Methods:this software is programmed by C# language,use database, and is based on the.NET network registration platform.It is constitute of three major modulars:the patients' information,the primary registration of the case file,and the follow-up and evaluation modular.The administration authority is used to ensure the validity and efficacy of the imported data.In the patients' information part,detailed personal information is the guarantee of the data validity.In the second part,stabile personal E-MAIL address is essential on account of the widespread application of network technology.And it facilitate the follow-up visit.The separation administration of the first visit case modular and the return visit case modular makes it possible to record one patient's data for many times,it facilitate the track evaluation for different diseases on the same patient,and finally,it makes the exactitude administration of the corresponding data come true.For research and teaching needs. To comply with the widespread application of the multi-media software,this system integrates a simple picture and video import system.Another special feature of this software is a standard,open evaluation system.The methods used in the evaluation system of this software are the commonly accepted standards.Considering the fast development of the medical practice,this system allows self composed evaluation methods to be carried out the preliminary evaluation on internet.Results:we successfully build up an easy to operate,free-of-charge,online, open and exactitude orthopedic case file registration software,it provides multiple data searching method,with it we can import and administrate data freely,and ensure the convenience and exactitude of the systematic review.Conclusion:online orthopedic case file system has great prospect in orthopedic clinical research and teaching,It provides an effective platform for orthopedic clinical communication,as well as an exactitude evaluation to the new technology and new treatments for orthopedic diseases.The application of the open registration and evaluation methods can effectively promote the improvement of the clinical evaluation methods and introduction of new methods.